Since current wired communication and mobile phone markets have matured, there are limitations in pursuing the development of communication industries through simple subscriber increase based on an existing service. On account of this, a portable Internet system has emerged as a new breakthrough of communication industries, which can not only use a 2.3 GHz band, but can also use an Internet service in stationary environments and mobile environments involving movement at various speeds by integrating mobile communication environments with wired communication environments. Hereinafter, technical backgrounds in which a portable Internet system has emerged will be briefly described.
A mobile communication system has developed from a first generation analog Advanced Mobile Phone System (AMPS) scheme, and a second generation cellular/portable communication service scheme, and has recently emerged into an International Mobile Telecommunication-2000 (IMT-2000) corresponding to a third generation high speed data communication. An IMT-2000 service may be classified as a Code Division Multiple Access (CDMA) 2000 1X service or a CDMA 2000 1X EV-DO service. A CDMA 2000 1X service denotes a service capable of providing a wireless Internet service at a maximum speed of 144 Kbps far faster than that of 14.4 Kbps or 56 Kbps, which is supported by an existing IS-95A or IS-95B network, by using an IS-95C network evolved from the IS-95A or IS-95B network. Accordingly, it becomes possible to not only improve the quality of existing voice and Wireless Application Protocol (WAP) services, but also to provide various multimedia services including an Audio On Demand (AOD), a Video On Demand (VOD), etc.
However, since a mobile communication system providing an existing wireless Internet service requires high base station installation costs, service charge for the wireless Internet service is high. Further, since a mobile communication terminal has a small screen size, usable contents are limited. Therefore, it is limited to provide an Internet service equal to that provided in wired Internet environments. Furthermore, in the case of using Wireless Local Area Network (WLAN) technology in a wireless Internet service, it is limited to smoothly provide the wireless Internet service due to radio wave interference, narrow coverage, the impossibility of service use in movement, etc. On account of this, a portable Internet system or a Wireless Broadband Internet (WBI) system has emerged, which can wirelessly use an Internet service at a low cost while in motion, which is equal to that provided in wired Internet environments. That is, a portable Internet system denotes a system which is located between a WLAN system and a wireless Internet system based on mobile communication, accesses the Internet in stationary environments and mobile environments involving movement at various speeds regardless of time and places by using a PDA, a notebook and various types of portable wireless terminals, and then provides a wireless Internet service capable of using various pieces of information and contents.
In a conventional portable Internet system, in other words, a mobile access system, research into a resource allocation method of the mobile access system has been actively conducted in order to satisfy QoS and to support various types of supplementary services. A representative resource allocation method of a mobile access system includes a Delay Threshold-based Priority Queueing (DTPQ) scheduling scheme. A DTPQ scheduling scheme denotes algorithm for setting a maximum delay threshold value in a realtime service and then scheduling processes required for a mobile access system in order to satisfy QoS requested by realtime and non-realtime service users, and to increase the capacity of the mobile access system.
A conventional DTPQ scheduling scheme used as algorithm for scheduling processes of a mobile access system has the following problems. That is, in the conventional DTPQ scheduling scheme, since only packet data exceeding a delay threshold value having the preset delay time of a Head of Line (HOL) is scheduled from among packet data provided in a realtime service, the mobile access system may be overloaded in a process of providing the realtime service. In short, in the DTPQ scheduling scheme, an optimal delay threshold value must be differently set in various service environments, i.e. since the number of realtime users and the number of non-realtime users change in the mobile access system, the delay threshold value must also change in consideration of this. However, since the optimal delay threshold value is fixed, the mobile access system may be overloaded in a process of providing the realtime service.